import org.json.simple.*;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class JsParser {
    public static void main(String [] args) throws ParseException {
        String json = "{\"paramsArray\": [\"first\", 100], "
                + "\"paramsObj\": {\"one\": \"two\", \"three\": \"four\"}, "
                + "\"paramsStr\": \"some string\"}";

        JSONParser parser = new JSONParser();

        Object obj = parser.parse(json);
        JSONObject jsonObj = (JSONObject) obj;
        System.out.println(jsonObj.get("paramsStr"));
        // some string

        JSONObject jo = (JSONObject) jsonObj.get("paramsObj");
        System.out.println(jo.get("three"));
        // four

        JSONArray ja = (JSONArray) jsonObj.get("paramsArray");
        System.out.println(ja.get(1));
        // 100
    }
}
